/*
** $Id: lstrlib.c,v 1.178 2012/08/14 18:12:34 roberto Exp $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/


#include <ctype.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define lstrlib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


/*
** maximum number of captures that a pattern can do during
** pattern-matching. This limit is arbitrary.
*/
#if !defined(LUA_MAXCAPTURES)
#define LUA_MAXCAPTURES		32
#endif


/* macro to `unsign' a character */
#define uchar(c)	((unsigned char)(c))



static int str_len (lua_State *L) {
	size_t l;
	luaL_checklstring(L, 1, &l);
	lua_pushinteger(L, (lua_Integer)l);
	return 1;
}


/* translate a relative string position: negative means back from end */
static size_t posrelat (ptrdiff_t pos, size_t len) {
	if (pos >= 0) return (size_t)pos;
	else if (0u - (size_t)pos > len) return 0;
	else return len - ((size_t)-pos) + 1;
}


static int str_sub (lua_State *L) {
	size_t l;
	const char *s = luaL_checklstring(L, 1, &l);
	size_t start = posrelat(luaL_checkinteger(L, 2), l);
	size_t end = posrelat(luaL_optinteger(L, 3, -1), l);
	if (start < 1) start = 1;
	if (end > l) end = l;
	if (start <= end)
		lua_pushlstring(L, s + start - 1, end - start + 1);
	else lua_pushliteral(L, "");
	return 1;
}


static int str_reverse (lua_State *L) {
	size_t l, i;
	luaL_Buffer b;
	const char *s = luaL_checklstring(L, 1, &l);
	char *p = luaL_buffinitsize(L, &b, l);
	for (i = 0; i < l; i++)
		p[i] = s[l - i - 1];
	luaL_pushresultsize(&b, l);
	return 1;
}


static int str_lower (lua_State *L) {
	size_t l;
	size_t i;
	luaL_Buffer b;
	const char *s = luaL_checklstring(L, 1, &l);
	char *p = luaL_buffinitsize(L, &b, l);
	for (i=0; i<l; i++)
		p[i] = tolower(uchar(s[i]));
	luaL_pushresultsize(&b, l);
	return 1;
}


static int str_upper (lua_State *L) {
	size_t l;
	size_t i;
	luaL_Buffer b;
	const char *s = luaL_checklstring(L, 1, &l);
	char *p = luaL_buffinitsize(L, &b, l);
	for (i=0; i<l; i++)
		p[i] = toupper(uchar(s[i]));
	luaL_pushresultsize(&b, l);
	return 1;
}


/* reasonable limit to avoid arithmetic overflow */
#define MAXSIZE		((~(size_t)0) >> 1)

static int str_rep (lua_State *L) {
	size_t l, lsep;
	const char *s = luaL_checklstring(L, 1, &l);
	int n = luaL_checkint(L, 2);
	const char *sep = luaL_optlstring(L, 3, "", &lsep);
	if (n <= 0) lua_pushliteral(L, "");
	else if (l + lsep < l || l + lsep >= MAXSIZE / n)  /* may overflow? */
		return luaL_error(L, "resulting string too large");
	else {
		size_t totallen = n * l + (n - 1) * lsep;
		luaL_Buffer b;
		char *p = luaL_buffinitsize(L, &b, totallen);
		while (n-- > 1) {  /* first n-1 copies (followed by separator) */
			memcpy(p, s, l * sizeof(char)); p += l;
			if (lsep > 0) {  /* avoid empty 'memcpy' (may be expensive) */
				memcpy(p, sep, lsep * sizeof(char)); p += lsep;
			}
		}
		memcpy(p, s, l * sizeof(char));  /* last copy (not followed by separator) */
		luaL_pushresultsize(&b, totallen);
	}
	return 1;
}


static int str_byte (lua_State *L) {
	size_t l;
	const char *s = luaL_checklstring(L, 1, &l);
	size_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
	size_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
	int n, i;
	if (posi < 1) posi = 1;
	if (pose > l) pose = l;
	if (posi > pose) return 0;  /* empty interval; return no values */
	n = (int)(pose -  posi + 1);
	if (posi + n <= pose)  /* (size_t -> int) overflow? */
		return luaL_error(L, "string slice too long");
	luaL_checkstack(L, n, "string slice too long");
	for (i=0; i<n; i++)
		lua_pushinteger(L, uchar(s[posi+i-1]));
	return n;
}


static int str_char (lua_State *L) {
	int n = lua_gettop(L);  /* number of arguments */
	int i;
	luaL_Buffer b;
	char *p = luaL_buffinitsize(L, &b, n);
	for (i=1; i<=n; i++) {
		int c = luaL_checkint(L, i);
		luaL_argcheck(L, uchar(c) == c, i, "value out of range");
		p[i - 1] = uchar(c);
	}
	luaL_pushresultsize(&b, n);
	return 1;
}


static int writer (lua_State *L, const void* b, size_t size, void* B) {
	(void)L;
	luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
	return 0;
}


static int str_dump (lua_State *L) {
	luaL_Buffer b;
	luaL_checktype(L, 1, LUA_TFUNCTION);
	lua_settop(L, 1);
	luaL_buffinit(L,&b);
	if (lua_dump(L, writer, &b) != 0)
		return luaL_error(L, "unable to dump given function");
	luaL_pushresult(&b);
	return 1;
}



/*
** {======================================================
** PATTERN MATCHING
** =======================================================
*/


#define CAP_UNFINISHED	(-1)
#define CAP_POSITION	(-2)


typedef struct MatchState {
	int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
	const char *src_init;  /* init of source string */
	const char *src_end;  /* end ('\0') of source string */
	const char *p_end;  /* end ('\0') of pattern */
	lua_State *L;
	int level;  /* total number of captures (finished or unfinished) */
	struct {
		const char *init;
		ptrdiff_t len;
	} capture[LUA_MAXCAPTURES];
} MatchState;


/* recursive function */
static const char *match (MatchState *ms, const char *s, const char *p);


/* maximum recursion depth for 'match' */
#if !defined(MAXCCALLS)
#define MAXCCALLS	200
#endif


#define L_ESC		'%'
#define SPECIALS	"^$*+?.([%-"


static int check_capture (MatchState *ms, int l) {
	l -= '1';
	if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
		return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
	return l;
}


static int capture_to_close (MatchState *ms) {
	int level = ms->level;
	for (level--; level>=0; level--)
		if (ms->capture[level].len == CAP_UNFINISHED) return level;
	return luaL_error(ms->L, "invalid pattern capture");
}


static const char *classend (MatchState *ms, const char *p) {
	switch (*p++) {
	case L_ESC: {
		if (p == ms->p_end)
			luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");
		return p+1;
				}
	case '[': {
		if (*p == '^') p++;
		do {  /* look for a `]' */
			if (p == ms->p_end)
				luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
			if (*(p++) == L_ESC && p < ms->p_end)
				p++;  /* skip escapes (e.g. `%]') */
		} while (*p != ']');
		return p+1;
			  }
	default: {
		return p;
			 }
	}
}


static int match_class (int c, int cl) {
	int res;
	switch (tolower(cl)) {
	case 'a' : res = isalpha(c); break;
	case 'c' : res = iscntrl(c); break;
	case 'd' : res = isdigit(c); break;
	case 'g' : res = isgraph(c); break;
	case 'l' : res = islower(c); break;
	case 'p' : res = ispunct(c); break;
	case 's' : res = isspace(c); break;
	case 'u' : res = isupper(c); break;
	case 'w' : res = isalnum(c); break;
	case 'x' : res = isxdigit(c); break;
	case 'z' : res = (c == 0); break;  /* deprecated option */
	default: return (cl == c);
	}
	return (islower(cl) ? res : !res);
}


static int matchbracketclass (int c, const char *p, const char *ec) {
	int sig = 1;
	if (*(p+1) == '^') {
		sig = 0;
		p++;  /* skip the `^' */
	}
	while (++p < ec) {
		if (*p == L_ESC) {
			p++;
			if (match_class(c, uchar(*p)))
				return sig;
		}
		else if ((*(p+1) == '-') && (p+2 < ec)) {
			p+=2;
			if (uchar(*(p-2)) <= c && c <= uchar(*p))
				return sig;
		}
		else if (uchar(*p) == c) return sig;
	}
	return !sig;
}


static int singlematch (MatchState *ms, const char *s, const char *p,
						const char *ep) {
							if (s >= ms->src_end)
								return 0;
							else {
								int c = uchar(*s);
								switch (*p) {
								case '.': return 1;  /* matches any char */
								case L_ESC: return match_class(c, uchar(*(p+1)));
								case '[': return matchbracketclass(c, p, ep-1);
								default:  return (uchar(*p) == c);
								}
							}
}


static const char *matchbalance (MatchState *ms, const char *s,
								 const char *p) {
									 if (p >= ms->p_end - 1)
										 luaL_error(ms->L, "malformed pattern "
										 "(missing arguments to " LUA_QL("%%b") ")");
									 if (*s != *p) return NULL;
									 else {
										 int b = *p;
										 int e = *(p+1);
										 int cont = 1;
										 while (++s < ms->src_end) {
											 if (*s == e) {
												 if (--cont == 0) return s+1;
											 }
											 else if (*s == b) cont++;
										 }
									 }
									 return NULL;  /* string ends out of balance */
}


static const char *max_expand (MatchState *ms, const char *s,
							   const char *p, const char *ep) {
								   ptrdiff_t i = 0;  /* counts maximum expand for item */
								   while (singlematch(ms, s + i, p, ep))
									   i++;
								   /* keeps trying to match with the maximum repetitions */
								   while (i>=0) {
									   const char *res = match(ms, (s+i), ep+1);
									   if (res) return res;
									   i--;  /* else didn't match; reduce 1 repetition to try again */
								   }
								   return NULL;
}


static const char *min_expand (MatchState *ms, const char *s,
							   const char *p, const char *ep) {
								   for (;;) {
									   const char *res = match(ms, s, ep+1);
									   if (res != NULL)
										   return res;
									   else if (singlematch(ms, s, p, ep))
										   s++;  /* try with one more repetition */
									   else return NULL;
								   }
}


static const char *start_capture (MatchState *ms, const char *s,
								  const char *p, int what) {
									  const char *res;
									  int level = ms->level;
									  if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
									  ms->capture[level].init = s;
									  ms->capture[level].len = what;
									  ms->level = level+1;
									  if ((res=match(ms, s, p)) == NULL)  /* match failed? */
										  ms->level--;  /* undo capture */
									  return res;
}


static const char *end_capture (MatchState *ms, const char *s,
								const char *p) {
									int l = capture_to_close(ms);
									const char *res;
									ms->capture[l].len = s - ms->capture[l].init;  /* close capture */
									if ((res = match(ms, s, p)) == NULL)  /* match failed? */
										ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */
									return res;
}


static const char *match_capture (MatchState *ms, const char *s, int l) {
	size_t len;
	l = check_capture(ms, l);
	len = ms->capture[l].len;
	if ((size_t)(ms->src_end-s) >= len &&
		memcmp(ms->capture[l].init, s, len) == 0)
		return s+len;
	else return NULL;
}


static const char *match (MatchState *ms, const char *s, const char *p) {
	if (ms->matchdepth-- == 0)
		luaL_error(ms->L, "pattern too complex");
init: /* using goto's to optimize tail recursion */
	if (p != ms->p_end) {  /* end of pattern? */
		switch (*p) {
		case '(': {  /* start capture */
			if (*(p + 1) == ')')  /* position capture? */
				s = start_capture(ms, s, p + 2, CAP_POSITION);
			else
				s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
			break;
				  }
		case ')': {  /* end capture */
			s = end_capture(ms, s, p + 1);
			break;
				  }
		case '$': {
			if ((p + 1) != ms->p_end)  /* is the `$' the last char in pattern? */
				goto dflt;  /* no; go to default */
			s = (s == ms->src_end) ? s : NULL;  /* check end of string */
			break;
				  }
		case L_ESC: {  /* escaped sequences not in the format class[*+?-]? */
			switch (*(p + 1)) {
			case 'b': {  /* balanced string? */
				s = matchbalance(ms, s, p + 2);
				if (s != NULL) {
					p += 4; goto init;  /* return match(ms, s, p + 4); */
				}  /* else fail (s == NULL) */
				break;
					  }
			case 'f': {  /* frontier? */
				const char *ep; char previous;
				p += 2;
				if (*p != '[')
					luaL_error(ms->L, "missing " LUA_QL("[") " after "
					LUA_QL("%%f") " in pattern");
				ep = classend(ms, p);  /* points to what is next */
				previous = (s == ms->src_init) ? '\0' : *(s - 1);
				if (!matchbracketclass(uchar(previous), p, ep - 1) &&
					matchbracketclass(uchar(*s), p, ep - 1)) {
						p = ep; goto init;  /* return match(ms, s, ep); */
				}
				s = NULL;  /* match failed */
				break;
					  }
			case '0': case '1': case '2': case '3':
			case '4': case '5': case '6': case '7':
			case '8': case '9': {  /* capture results (%0-%9)? */
				s = match_capture(ms, s, uchar(*(p + 1)));
				if (s != NULL) {
					p += 2; goto init;  /* return match(ms, s, p + 2) */
				}
				break;
					  }
			default: goto dflt;
			}
			break;
					}
		default: dflt: {  /* pattern class plus optional suffix */
			const char *ep = classend(ms, p);  /* points to optional suffix */
			/* does not match at least once? */
			if (!singlematch(ms, s, p, ep)) {
				if (*ep == '*' || *ep == '?' || *ep == '-') {  /* accept empty? */
					p = ep + 1; goto init;  /* return match(ms, s, ep + 1); */
				}
				else  /* '+' or no suffix */
					s = NULL;  /* fail */
			}
			else {  /* matched once */
				switch (*ep) {  /* handle optional suffix */
				case '?': {  /* optional */
					const char *res;
					if ((res = match(ms, s + 1, ep + 1)) != NULL)
						s = res;
					else {
						p = ep + 1; goto init;  /* else return match(ms, s, ep + 1); */
					}
					break;
						  }
				case '+':  /* 1 or more repetitions */
					s++;  /* 1 match already done */
					/* go through */
				case '*':  /* 0 or more repetitions */
					s = max_expand(ms, s, p, ep);
					break;
				case '-':  /* 0 or more repetitions (minimum) */
					s = min_expand(ms, s, p, ep);
					break;
				default:  /* no suffix */
					s++; p = ep; goto init;  /* return match(ms, s + 1, ep); */
				}
			}
			break;
				 }
		}
	}
	ms->matchdepth++;
	return s;
}



static const char *lmemfind (const char *s1, size_t l1,
							 const char *s2, size_t l2) {
								 if (l2 == 0) return s1;  /* empty strings are everywhere */
								 else if (l2 > l1) return NULL;  /* avoids a negative `l1' */
								 else {
									 const char *init;  /* to search for a `*s2' inside `s1' */
									 l2--;  /* 1st char will be checked by `memchr' */
									 l1 = l1-l2;  /* `s2' cannot be found after that */
									 while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
										 init++;   /* 1st char is already checked */
										 if (memcmp(init, s2+1, l2) == 0)
											 return init-1;
										 else {  /* correct `l1' and `s1' to try again */
											 l1 -= init-s1;
											 s1 = init;
										 }
									 }
									 return NULL;  /* not found */
								 }
}


static void push_onecapture (MatchState *ms, int i, const char *s,
							 const char *e) {
								 if (i >= ms->level) {
									 if (i == 0)  /* ms->level == 0, too */
										 lua_pushlstring(ms->L, s, e - s);  /* add whole match */
									 else
										 luaL_error(ms->L, "invalid capture index");
								 }
								 else {
									 ptrdiff_t l = ms->capture[i].len;
									 if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
									 if (l == CAP_POSITION)
										 lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
									 else
										 lua_pushlstring(ms->L, ms->capture[i].init, l);
								 }
}


static int push_captures (MatchState *ms, const char *s, const char *e) {
	int i;
	int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
	luaL_checkstack(ms->L, nlevels, "too many captures");
	for (i = 0; i < nlevels; i++)
		push_onecapture(ms, i, s, e);
	return nlevels;  /* number of strings pushed */
}


/* check whether pattern has no special characters */
static int nospecials (const char *p, size_t l) {
	size_t upto = 0;
	do {
		if (strpbrk(p + upto, SPECIALS))
			return 0;  /* pattern has a special character */
		upto += strlen(p + upto) + 1;  /* may have more after \0 */
	} while (upto <= l);
	return 1;  /* no special chars found */
}


static int str_find_aux (lua_State *L, int find) {
	size_t ls, lp;
	const char *s = luaL_checklstring(L, 1, &ls);
	const char *p = luaL_checklstring(L, 2, &lp);
	size_t init = posrelat(luaL_optinteger(L, 3, 1), ls);
	if (init < 1) init = 1;
	else if (init > ls + 1) {  /* start after string's end? */
		lua_pushnil(L);  /* cannot find anything */
		return 1;
	}
	/* explicit request or no special characters? */
	if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
		/* do a plain search */
		const char *s2 = lmemfind(s + init - 1, ls - init + 1, p, lp);
		if (s2) {
			lua_pushinteger(L, s2 - s + 1);
			lua_pushinteger(L, s2 - s + lp);
			return 2;
		}
	}
	else {
		MatchState ms;
		const char *s1 = s + init - 1;
		int anchor = (*p == '^');
		if (anchor) {
			p++; lp--;  /* skip anchor character */
		}
		ms.L = L;
		ms.matchdepth = MAXCCALLS;
		ms.src_init = s;
		ms.src_end = s + ls;
		ms.p_end = p + lp;
		do {
			const char *res;
			ms.level = 0;
			lua_assert(ms.matchdepth == MAXCCALLS);
			if ((res=match(&ms, s1, p)) != NULL) {
				if (find) {
					lua_pushinteger(L, s1 - s + 1);  /* start */
					lua_pushinteger(L, res - s);   /* end */
					return push_captures(&ms, NULL, 0) + 2;
				}
				else
					return push_captures(&ms, s1, res);
			}
		} while (s1++ < ms.src_end && !anchor);
	}
	lua_pushnil(L);  /* not found */
	return 1;
}


static int str_find (lua_State *L) {
	return str_find_aux(L, 1);
}


static int str_match (lua_State *L) {
	return str_find_aux(L, 0);
}


static int gmatch_aux (lua_State *L) {
	MatchState ms;
	size_t ls, lp;
	const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
	const char *p = lua_tolstring(L, lua_upvalueindex(2), &lp);
	const char *src;
	ms.L = L;
	ms.matchdepth = MAXCCALLS;
	ms.src_init = s;
	ms.src_end = s+ls;
	ms.p_end = p + lp;
	for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
		src <= ms.src_end;
		src++) {
			const char *e;
			ms.level = 0;
			lua_assert(ms.matchdepth == MAXCCALLS);
			if ((e = match(&ms, src, p)) != NULL) {
				lua_Integer newstart = e-s;
				if (e == src) newstart++;  /* empty match? go at least one position */
				lua_pushinteger(L, newstart);
				lua_replace(L, lua_upvalueindex(3));
				return push_captures(&ms, src, e);
			}
	}
	return 0;  /* not found */
}


static int gmatch (lua_State *L) {
	luaL_checkstring(L, 1);
	luaL_checkstring(L, 2);
	lua_settop(L, 2);
	lua_pushinteger(L, 0);
	lua_pushcclosure(L, gmatch_aux, 3);
	return 1;
}


static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
				   const char *e) {
					   size_t l, i;
					   const char *news = lua_tolstring(ms->L, 3, &l);
					   for (i = 0; i < l; i++) {
						   if (news[i] != L_ESC)
							   luaL_addchar(b, news[i]);
						   else {
							   i++;  /* skip ESC */
							   if (!isdigit(uchar(news[i]))) {
								   if (news[i] != L_ESC)
									   luaL_error(ms->L, "invalid use of " LUA_QL("%c")
									   " in replacement string", L_ESC);
								   luaL_addchar(b, news[i]);
							   }
							   else if (news[i] == '0')
								   luaL_addlstring(b, s, e - s);
							   else {
								   push_onecapture(ms, news[i] - '1', s, e);
								   luaL_addvalue(b);  /* add capture to accumulated result */
							   }
						   }
					   }
}


static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
					   const char *e, int tr) {
						   lua_State *L = ms->L;
						   switch (tr) {
						   case LUA_TFUNCTION: {
							   int n;
							   lua_pushvalue(L, 3);
							   n = push_captures(ms, s, e);
							   lua_call(L, n, 1);
							   break;
											   }
						   case LUA_TTABLE: {
							   push_onecapture(ms, 0, s, e);
							   lua_gettable(L, 3);
							   break;
											}
						   default: {  /* LUA_TNUMBER or LUA_TSTRING */
							   add_s(ms, b, s, e);
							   return;
									}
						   }
						   if (!lua_toboolean(L, -1)) {  /* nil or false? */
							   lua_pop(L, 1);
							   lua_pushlstring(L, s, e - s);  /* keep original text */
						   }
						   else if (!lua_isstring(L, -1))
							   luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
						   luaL_addvalue(b);  /* add result to accumulator */
}


static int str_gsub (lua_State *L) {
	size_t srcl, lp;
	const char *src = luaL_checklstring(L, 1, &srcl);
	const char *p = luaL_checklstring(L, 2, &lp);
	int tr = lua_type(L, 3);
	size_t max_s = luaL_optinteger(L, 4, srcl+1);
	int anchor = (*p == '^');
	size_t n = 0;
	MatchState ms;
	luaL_Buffer b;
	luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
		tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
		"string/function/table expected");
	luaL_buffinit(L, &b);
	if (anchor) {
		p++; lp--;  /* skip anchor character */
	}
	ms.L = L;
	ms.matchdepth = MAXCCALLS;
	ms.src_init = src;
	ms.src_end = src+srcl;
	ms.p_end = p + lp;
	while (n < max_s) {
		const char *e;
		ms.level = 0;
		lua_assert(ms.matchdepth == MAXCCALLS);
		e = match(&ms, src, p);
		if (e) {
			n++;
			add_value(&ms, &b, src, e, tr);
		}
		if (e && e>src) /* non empty match? */
			src = e;  /* skip it */
		else if (src < ms.src_end)
			luaL_addchar(&b, *src++);
		else break;
		if (anchor) break;
	}
	luaL_addlstring(&b, src, ms.src_end-src);
	luaL_pushresult(&b);
	lua_pushinteger(L, n);  /* number of substitutions */
	return 2;
}

/* }====================================================== */



/*
** {======================================================
** STRING FORMAT
** =======================================================
*/

/*
** LUA_INTFRMLEN is the length modifier for integer conversions in
** 'string.format'; LUA_INTFRM_T is the integer type corresponding to
** the previous length
*/
#if !defined(LUA_INTFRMLEN)	/* { */
#if defined(LUA_USE_LONGLONG)

#define LUA_INTFRMLEN		"ll"
#define LUA_INTFRM_T		long long

#else

#define LUA_INTFRMLEN		"l"
#define LUA_INTFRM_T		long

#endif
#endif				/* } */


/*
** LUA_FLTFRMLEN is the length modifier for float conversions in
** 'string.format'; LUA_FLTFRM_T is the float type corresponding to
** the previous length
*/
#if !defined(LUA_FLTFRMLEN)

#define LUA_FLTFRMLEN		""
#define LUA_FLTFRM_T		double

#endif


/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
#define MAX_ITEM	512
/* valid flags in a format specification */
#define FLAGS	"-+ #0"
/*
** maximum size of each format specification (such as '%-099.99d')
** (+10 accounts for %99.99x plus margin of error)
*/
#define MAX_FORMAT	(sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)


static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
	size_t l;
	const char *s = luaL_checklstring(L, arg, &l);
	luaL_addchar(b, '"');
	while (l--) {
		if (*s == '"' || *s == '\\' || *s == '\n') {
			luaL_addchar(b, '\\');
			luaL_addchar(b, *s);
		}
		else if (*s == '\0' || iscntrl(uchar(*s))) {
			char buff[10];
			if (!isdigit(uchar(*(s+1))))
				sprintf(buff, "\\%d", (int)uchar(*s));
			else
				sprintf(buff, "\\%03d", (int)uchar(*s));
			luaL_addstring(b, buff);
		}
		else
			luaL_addchar(b, *s);
		s++;
	}
	luaL_addchar(b, '"');
}

static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
	const char *p = strfrmt;
	while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */
	if ((size_t)(p - strfrmt) >= sizeof(FLAGS)/sizeof(char))
		luaL_error(L, "invalid format (repeated flags)");
	if (isdigit(uchar(*p))) p++;  /* skip width */
	if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
	if (*p == '.') {
		p++;
		if (isdigit(uchar(*p))) p++;  /* skip precision */
		if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
	}
	if (isdigit(uchar(*p)))
		luaL_error(L, "invalid format (width or precision too long)");
	*(form++) = '%';
	memcpy(form, strfrmt, (p - strfrmt + 1) * sizeof(char));
	form += p - strfrmt + 1;
	*form = '\0';
	return p;
}


/*
** add length modifier into formats
*/
static void addlenmod (char *form, const char *lenmod) {
	size_t l = strlen(form);
	size_t lm = strlen(lenmod);
	char spec = form[l - 1];
	strcpy(form + l - 1, lenmod);
	form[l + lm - 1] = spec;
	form[l + lm] = '\0';
}


static int str_format (lua_State *L) {
	int top = lua_gettop(L);
	int arg = 1;
	size_t sfl;
	const char *strfrmt = luaL_checklstring(L, arg, &sfl);
	const char *strfrmt_end = strfrmt+sfl;
	luaL_Buffer b;
	luaL_buffinit(L, &b);
	while (strfrmt < strfrmt_end) {
		if (*strfrmt != L_ESC)
			luaL_addchar(&b, *strfrmt++);
		else if (*++strfrmt == L_ESC)
			luaL_addchar(&b, *strfrmt++);  /* %% */
		else { /* format item */
			char form[MAX_FORMAT];  /* to store the format (`%...') */
			char *buff = luaL_prepbuffsize(&b, MAX_ITEM);  /* to put formatted item */
			int nb = 0;  /* number of bytes in added item */
			if (++arg > top)
				luaL_argerror(L, arg, "no value");
			strfrmt = scanformat(L, strfrmt, form);
			switch (*strfrmt++) {
			case 'c': {
				nb = sprintf(buff, form, luaL_checkint(L, arg));
				break;
					  }
			case 'd': case 'i': {
				lua_Number n = luaL_checknumber(L, arg);
				LUA_INTFRM_T ni = (LUA_INTFRM_T)n;
				lua_Number diff = n - (lua_Number)ni;
				luaL_argcheck(L, -1 < diff && diff < 1, arg,
					"not a number in proper range");
				addlenmod(form, LUA_INTFRMLEN);
				nb = sprintf(buff, form, ni);
				break;
					  }
			case 'o': case 'u': case 'x': case 'X': {
				lua_Number n = luaL_checknumber(L, arg);
				unsigned LUA_INTFRM_T ni = (unsigned LUA_INTFRM_T)n;
				lua_Number diff = n - (lua_Number)ni;
				luaL_argcheck(L, -1 < diff && diff < 1, arg,
					"not a non-negative number in proper range");
				addlenmod(form, LUA_INTFRMLEN);
				nb = sprintf(buff, form, ni);
				break;
					  }
			case 'e': case 'E': case 'f':
#if defined(LUA_USE_AFORMAT)
			case 'a': case 'A':
#endif
			case 'g': case 'G': {
				addlenmod(form, LUA_FLTFRMLEN);
				nb = sprintf(buff, form, (LUA_FLTFRM_T)luaL_checknumber(L, arg));
				break;
					  }
			case 'q': {
				addquoted(L, &b, arg);
				break;
					  }
			case 's': {
				size_t l;
				const char *s = luaL_tolstring(L, arg, &l);
				if (!strchr(form, '.') && l >= 100) {
					/* no precision and string is too long to be formatted;
					keep original string */
					luaL_addvalue(&b);
					break;
				}
				else {
					nb = sprintf(buff, form, s);
					lua_pop(L, 1);  /* remove result from 'luaL_tolstring' */
					break;
				}
					  }
			default: {  /* also treat cases `pnLlh' */
				return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
					LUA_QL("format"), *(strfrmt - 1));
					 }
			}
			luaL_addsize(&b, nb);
		}
	}
	luaL_pushresult(&b);
	return 1;
}

/* }====================================================== */


static const luaL_Reg strlib[] = {
	{"byte", str_byte},
	{"char", str_char},
	{"dump", str_dump},
	{"find", str_find},
	{"format", str_format},
	{"gmatch", gmatch},
	{"gsub", str_gsub},
	{"len", str_len},
	{"lower", str_lower},
	{"match", str_match},
	{"rep", str_rep},
	{"reverse", str_reverse},
	{"sub", str_sub},
	{"upper", str_upper},
	{NULL, NULL}
};


static void createmetatable (lua_State *L) {
	lua_createtable(L, 0, 1);  /* table to be metatable for strings */
	lua_pushliteral(L, "");  /* dummy string */
	lua_pushvalue(L, -2);  /* copy table */
	lua_setmetatable(L, -2);  /* set table as metatable for strings */
	lua_pop(L, 1);  /* pop dummy string */
	lua_pushvalue(L, -2);  /* get string library */
	lua_setfield(L, -2, "__index");  /* metatable.__index = string */
	lua_pop(L, 1);  /* pop metatable */
}


/*
** Open string library
*/
LUAMOD_API int luaopen_string (lua_State *L) {
	luaL_newlib(L, strlib);
	createmetatable(L);
	return 1;
}

